We developed this product to relieve pressure when we transferred or filtered beer from one keg to another. This connects to the keg you are filtering into and has adjustable relief valve for letting pressure off as the keg fills up.

Notes: The very end of the pressure relief valve can be adjusted by unscrewing to adjust the pressure. If tight, and not adjustable by hand, it needs to be loosened with pliers. Wrap a towel around the end piece of the pressure relief valve (about the last 1/4 in) and loosen with pliers. Then finger tighten or loosen to desired pressure.

Having an adjustable pressure relief valve is great for closed environment CO2 transfers, and especially helpful for keg to keg transfers of carbonated beer. The adjustment to the pressure relief is fairly crude (tends to jump with little adjustments). A tighter tolerance for the threads would probably help. That said, it's better than not having one, and beats the hell out of the old process of pulling the pressure relief valve to stay all the way open, or burping it. I wish I would have opted for the more expensive one with the gauge. My only suggestion for improvement is a tighter tolerance on the threads for the adjustment for the pressure.